Wireless data communication is a critical component of mobile computing and has become increasingly developed due to the continued progress of mobile computing technologies, the popularity of mobile computing products, and the deployment of numerous, comprehensive infrastructure buildouts providing wireless communication services to the mobile computing products. A typical wireless communication system may be implemented as a multiple access system—capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems may include code division multiple access (CDMA) systems, high speed packet access (HSPA), wideband code division multiple access (W-CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, among others. Additionally, the systems can conform to specifications such as those promulgated by the Third Generation Partnership Project (3GPP), such as 3GPP Rel. 8 and 9 pertaining to “Long Term Evolution” (LTE), 3GPP Rel. 10 and 11 pertaining to LTE-Advanced, as well as specifications such as ultra mobile broadband (UMB) and WiMAX promulgated by other entities.
Generally, wireless multiple access communication systems may support simultaneous communication for multiple mobile devices in a network. Each mobile device (also referred to as “user equipment” or “UE”) may communicate with an operator network (e.g., a cellular network or other mobile devices by connecting to one or more access points (e.g., base stations, relay nodes, etc) of the network, typically via radio frequency (RF) transmissions. The various available technologies that comprise the spectrum of wireless data communications often differ in local availability, coverage range, and performance. Cellular networks are one type of wireless data network, where wireless service is provided over a geographical area, and this service area is divided into a number of smaller (sometimes overlapping) regions known as cells. Each cell is served by at least one generally fixed-location transceiver known as a cell site, node, base station, or base transceiver station (BTS). Individual nodes are also commonly referred to as node base stations (“node Bs”), or eNB (“enhanced node base stations”). When joined together, the network provided by these cells, stations, and/or nodes can cover a significantly wide area. This enables a large number of user-operated mobile computing devices (e.g., mobile phones, tablets, laptops, etc.) to communicate with other nodes in the network via the base stations.
In an OFDMA communication system, each frequency channel, or bandwidth, is split into multiple contiguous Resource Blocks (RBs). Furthermore, multiple RBs may be grouped together to form a Resource Block Group (RBG). A base station then assigns the RBs to user equipment devices (UEs). Data is allocated to the UEs in terms of resource blocks. For any given Transmission Time Interval (TTI), the RBs are allocated to UEs based on measured channel conditions. The channel condition measurements are performed by a user equipment (UE), which measures channel conditions for one or more RBGs during a measuring period. The UE can report the measured channel conditions for the RBG to the servicing base station. In accordance with the reported Channel Quality Information (CQI) message, an OFDMA communication system is able to selectively schedule the RBs over a scheduling period, typically lasting one or more TTIs or radio frames. The scheduling decision—which is typically performed in the base station—can be modified every transmission time interval (TTI), and takes into account the radio link quality situation of different users, the overall interference situation, Quality of Service requirements, service priorities and other considerations.
Standards such as LTE specify that UEs can only assume a certain number of quantized power levels, also known as PA (Power Assignment) values. These PA values are communicated periodically (e.g. minutes level) to UEs through Radio Resource Control (RRC) signaling and typically cannot be changed on the fly. As a result, power control schemes for base stations generally assign multiple PA values to the UEs in the downlink (transmission). Unfortunately, assignment of these PA values impacts the load balancing between different power levels in a cell and has to be done properly in order to ensure a suitable tradeoff between throughput and coverage within each cell.
Conventional inter-cell interference coordination (ICIC) schemes such as the Soft Frequency Reuse (SFR) technique, rely on RB power mask coordination between different cells in order to reduce the level of interference due to neighboring cells in the network. This is often achieved by boosting (via a pre-defined power mask) the power used to transmit data for a fixed and pre-determined set of RBs, while the power assigned to other RBs is reduced in order to abide by the total power constraint. To reduce redundancy, and further reduce interference, each cell will coordinate and cooperate with neighboring cells such that power-boosted RBs are not assigned to the same vicinities. While this solution can be effective in a network dominated by inter-cell interference, having a pre-determined power mask can also limit performance (e.g., average cell throughput) under Frequency Selective Scheduling (FSS) systems because cell edge UEs (power boosted UEs) are constrained to use the pre-set power boosted RBs and can no longer enjoy the flexibility to be scheduled over the whole bandwidth.
Moreover, while these solutions are suitable for interference-dominated scenarios, in noise (rather than interference) dominated scenarios, reducing inter-cell interference is not an effective solution, since the performance of the network is not significantly impacted by interference. Therefore the use of conventional techniques directed to solving interference problems in a noise-dominated scenario will only incur the loss of average cell throughput without realizing any of the solution's purported advantages.